As is well known in the art, cellular telephones which have exhibited a rapid proliferation in recent years have not only a function merely as mobile or portable telephones but also a function as mobile terminal devices. Specifically, it is possible to connect to the Internet through a cellular telephone, and there is a widespread proliferation of sending and receiving pieces of e-mail by using a cellular telephone (See Patent Document 1 as an example). Cellular telephones themselves become more sophisticated in functionality, and various function settings of cellular telephones can be made to suit the preferences of users. Further, cellular telephones incorporating hard disks have been developed in recent years.
For sending a piece of e-mail, for example, from a cellular telephone, it is conventionally common practice to select a desired e-mail address from among a multiplicity of e-mail addresses registered in an address book, thereby determining the selected e-mail address as a destination to which the piece of e-mail is to be sent. To specify the destination of a piece of e-mail, such a process has been widely adopted that a user performs a predetermined manipulation by using dial keys to open an address book, and selects the destination from a displayed list thereof via the dial keys. For function settings of the cellular telephone, such a process has been prevailing that the user performs a predetermined manipulation by using the dial keys to follow a menu screen, selects a necessary item from a menu, and performs a setting manipulation.
Patent Document 1: Japanese Patent Application Laid-Open No. 2001-257711
In the above-mentioned manner, the manipulations of calling up registration information (registered e-mail addresses and functions) to make a selection are very often performed on the cellular telephone. However, the number of dial keys that can be arranged on the cellular telephone is limited to approximately twenty at most because of size limitations, and the user manipulates the approximately twenty keys to make a selection from among various pieces of registration information and to set the various pieces of registration information. Thus, the operability of cellular telephones is much inferior to that of personal computers and the like each having a keyboard and a mouse, and there has been a problem such that the more sophisticated the functionality of cellular telephones becomes, the more cumbersome the operability for calling up the registration information inevitably becomes.